One correction: while its equally constructivist i.e. the emphasis is on student direct problem solving as the primary means to learning math, CMP does not spiral in the same way Every Day Math does.
You might want to look at:
http://connectedmath.msu.edu/the-math/math-by-unit/ for a description of what is covered in 6th grade.
CMP has reputation for not really building on prior units as it moves forward so your risk is more about leaving holes in your daughters knowledge rather than having a bad transition.
Thank you and yes, that is another concern of mine (the holes). I spoke to her principal today and she assured me that the instructors who are teaching the 5th graders this 7th grade curriculum understand that they are missing some basic foundational instruction and will take the time to teach them and help fill the gaps as they go. If not, I will probably be doing partial home schooling to help, which sadly I have just grown used too. Regardless, I have to view this as a great opportunity for DD because her lower elementary offered no differentiation or gifted classes and she has been bored out of her mind in math for the past 5 years. Plus, the other upside to this is that they differentiate the actual classroom based on the math class that the students are assigned to, so that means she should be in a classroom with other advanced kids, which will be nice to have a classroom of like minded peers.
Thank you everyone for your input and information. I hope this works out well for us in the fall. Sadly, we are stuck with the curriculum mandated by the state, however, our school district is very well funded and high achieving and they take the time to supplement "real" math to the curriculum to ensure that the kids learn what they need to know to be successful later on in their education.